<template>
  <div id="app" v-cloak>
    <div class="container">
      <div class="prize-list" ref="prizeWrap" :style="bgColor">
        <div class="prize-item" v-for="(item, index) in state.prizeList" :style="prizeStyle(index)">
          <img :src="item.pic" alt="">
          <p>{{ item.name }}</p>
        </div>
      </div>
      <div class="btn" @click="start"></div>
    </div>
  </div>
</template>

<script setup lang="ts">
import { onMounted, onUnmounted, ref, reactive, computed } from  'vue'
const state = reactive({
  prizeList: [
    { name: '手机', pic: 'https://t14.baidu.com/it/u=1907298832,2489650453&fm=224&app=112&f=JPEG?w=500&h=500' },
    { name: '手表', pic: 'https://img1.baidu.com/it/u=2631716577,1296460670&fm=253&fmt=auto&app=120&f=JPEG' },
    { name: '苹果', pic: 'https://img2.baidu.com/it/u=2611478896,137965957&fm=253&fmt=auto&app=138&f=JPEG' },
    { name: '棒棒糖', pic: 'https://img2.baidu.com/it/u=576980037,1655121105&fm=253&fmt=auto&app=138&f=PNG' },
    { name: '娃娃', pic: 'https://img2.baidu.com/it/u=4075390137,3967712457&fm=253&fmt=auto&app=138&f=PNG' },
    { name: '木马', pic: 'https://img1.baidu.com/it/u=2434318933,2727681086&fm=253&fmt=auto&app=120&f=JPEG' },
    { name: '德芙', pic: 'https://img0.baidu.com/it/u=1378564582,2397555841&fm=253&fmt=auto&app=120&f=JPEG' },
    { name: '谢谢参与', pic: 'https://www.2bulu.com/js/2bulu_app/lotterydraw/img/joinfree.png' },
  ], // 后台配置的奖品数据
  isRunning: false, // 是否正在抽奖
  baseRunAngle: 360 * 5, // 总共转动角度 至少5圈
  prizeId: 0, // 中奖id
})
const prizeWrap = ref()


// 平均每个奖品角度
const rotateAngle = computed(() => {
  const _degree = 360 / state.prizeList.length
  return _degree
})

// 要执行总角度数
const totalRunAngle = computed(() => {
  return state.baseRunAngle + 360 - state.prizeId * rotateAngle.value - rotateAngle.value / 2
})

// 计算绘制转盘背景
const bgColor = computed(() => {
  const _len = state.prizeList.length
  const colorList = ['#5352b3', '#363589']
  let colorVal = ''
  for (let i = 0; i < _len; i++) {
    colorVal += `${colorList[i % 2]} ${rotateAngle.value * i}deg ${rotateAngle.value * (i + 1)}deg,`
  }
  return `
            background: conic-gradient(${colorVal.slice(0, -1)});
          `
})
// 每个奖品布局
const prizeStyle = computed(() => {
  const _degree = rotateAngle.value
  return (i) => {
    return `
              width: ${2 * 270 * Math.sin(_degree / 2 * Math.PI / 180)}px;
              height: 270px;
              transform: rotate(${_degree * i + _degree / 2}deg);
              transform-origin: 50% 100%;
            `
  }
})

onMounted(() => {
  prizeWrap.value.style = `${bgColor.value} transform: rotate(-${rotateAngle.value / 2}deg)`
})

onUnmounted(() => {
  if(prizeWrap.value){
    prizeWrap.value.removeEventListener('transitionend', stopRun)
  }
})

// 获取随机数
const getRandomNum = () => {
  const num = Math.floor(Math.random() * state.prizeList.length)
  return num
}

const start = () => {
  if (!state.isRunning) {
    state.isRunning = true
    console.log('开始抽奖，后台请求中奖奖品')
    // 请求返回的奖品编号 这里使用随机数
    const prizeId = getRandomNum()
    console.log('中奖ID>>>', prizeId, state.prizeList[prizeId])
    state.prizeId = prizeId
    startRun()
  }
}

const startRun = () => {
  console.log(state.isRunning, totalRunAngle.value)
  // 设置动效
  prizeWrap.value.style = `
            ${bgColor.value}
            transform: rotate(${totalRunAngle.value}deg);
            transition: all 4s ease;
          `
  // 监听transition动效停止事件
  prizeWrap.value.addEventListener('transitionend', stopRun)
}

const stopRun = (e) => {
  console.log(e)
  state.isRunning = false
  prizeWrap.value.style = `
            ${bgColor.value}
            transform: rotate(${totalRunAngle.value - state.baseRunAngle}deg);
          `
}
</script>

<style scoped>
[v-cloak] {
  display: none;
}
.container {
  width: 540px;
  height: 540px;
  /*background: #98d3fc url('https://www.jq22.com/demo/vue-luck-draw-pdmm202010260015/img/bg.a4b976d5.png') no-repeat center / 100% 100%;*/
  /*background: conic-gradient(
   red 6deg, orange 6deg 18deg, yellow 18deg 45deg,
   green 45deg 110deg, blue 110deg 200deg, purple 200deg);*/
  margin: 100px auto;
  position: relative;
}
.prize-list {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  border: 10px solid #98d3fc;
  overflow: hidden;
}
.prize-item {
  /*border: 2px solid red;*/
  position: absolute;
  left: 0;
  right: 0;
  top: -10px;
  margin: auto;
}
.prize-item img {
  width: 30%;
  height: 20%;
  margin: 40px auto 10px;
  display: block;
}
.prize-item p {
  color: #fff;
  font-size: 12px;
  text-align: center;
  line-height: 20px;
}
.btn {
  width: 160px;
  height: 160px;
  background: url('https://www.jq22.com/demo/jquerylocal201912122316/img/btn_lottery.png') no-repeat center / 100% 100%;
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  margin: auto;
  cursor: pointer;
}
.btn::before {
  content: "";
  width: 41px;
  height: 39px;
  background: url('https://www.jq22.com/demo/jquerylocal201912122316/img/icon_point.png') no-repeat center / 100% 100%;
  position: absolute;
  left: 0;
  right: 0;
  top: -33px;
  margin: auto;
}
</style>